YICHANG, July 1 -- Flood season for the Yangtze River, China's longest, has begun this year due to the continuous rains in its middle and upper reaches, said authorities on Tuesday.

Water flow into the reservoir of the Three Gorges Dam stood at more than 15,000 cubic meters per second over the past ten days, said the Three Gorges Dam Navigation Bureau.

The water flow into the reservoir hit 20, 000 cubic meters per second at 2 p. m. Tuesday and the water level of the upper reaches of the Three Gorges stood at about 146.35 meters.

Maritime authorities have been on alert around-the-clock for any emergencies.

As the world's largest hydropower project, the Three Gorges Project consists of a dam, five-tier ship docks and a total of 32 hydropower turbo-generators.

Floods have claimed 134 lives and left 12 people missing in China so far this year, said the State Flood Control and Drought Relief Headquarters on Tuesday.